N-tetrahaloethylthio pyrazoles as bactericides and fungicides

ABSTRACT

N-(1,1,2,2-TERTRAHALOETHYLTHIO) PYRAZOLES IN WHICH THE PYRAZOLE NUCLEUS IS SUBSTITUTED IN THE 3 AND 5 POSITIONS WITH HYDROGEN OR LOWER ALKYL GROUPS AND IN THE 4 POSITION WITH HYDROGEN, HALOGEN OR A NITRO GROUP. COMPOUNDS OF THIS CLASS ARE FUNGICIDAL AND BACTERICIDAL. THEY ARE MADE BY REACTING A PYRAZOLE OR ITS ALKALI METAL SALT WITH TETRAHALOETHYLSULFENYL HALIDES.

Umted States Patent O 3,577,545 N-TETRAHALOETHYLTHIO PYRAZOLES AS BACTERICIDES AND FUNGICIDES Joseph G. E. Fenyes, Oakland, Calif., assignor to Chevron Research Company, San Francisco, Calif.

No Drawing. Original application June 5, 1967, Ser. No. 643,415, now Patent No. 3,409,632, dated Nov. 5, 1968. Divided and this application Dec. 21, 1967, Ser.

Int. 'Cl. A01n 9/22 US. Cl. 424-273 8 Claims ABSTRACT OF THE DISCLOSURE N-(1,1,2,2-tetrahaloethy1thio) pyrazoles in which the pyrazole nucleus is substituted in the 3 and positions with hydrogen or lower alkyl groups and in the 4 position with hydrogen, halogen or a nitro group. Compounds of this class are fungicidal and bactericidal. They are made by reacting a pyrazole or its alkali metal salt with tetrahaloethylsulfenyl halides.

CROSS REFERENCES TO RELATED APPLICATIONS This application is a divisional of copending application Ser. No. 643,415 filed June 5, 1967, now US. Pat. No. 3,409,632, which in turn is a continuation-in-part of copending application Ser. No. 573,878, filed Aug. 22, 1966 now abandoned.

FIELD OF INVENTION This invention is directed to novel N-tetrahaloethylthio pyrazoles which are useful as pesticides. More particularly, it concerns N-(1,1,2,2 tetrahaloethylthio)-pyrazoles and their use as bactericides and fungicides.

INVENTION DESCRIPTION These unique compounds are N-tetrahaloethylthio pyrazoles in which the pyrazole nucleus is substituted in the 3 and 5 positions with hydrogen or alkyl groups having 1 to 4 carbon atoms and in the 4 position with hydrogen, halogen of atomic number 17 to 35, i.e., chlorine or bromine or a nitro group. These pyrazoles may be represented by the general formula A i? l r stx X where X is halogen of atomic number 17 to 35, R and R are individually hydrogen or alkyl of 1 to 4 carbon atoms and R is hydrogen, halogen of atomic number 17 to 35 or a nitro group. Preferably, R R and R are hydrogen and X is chlorine. A preferred alkyl group for R and R is methyl.

Specific examples of these novel compounds are:

The N-(1,1,2,2 tetrahaloethylthio) pyrazoles of this invention may be prepared by reacting 1,1,2,2-tetrahaloethylsulfenyl halide with pyrazole or a suitably substituted pyrazole. If desired, the alkali metal salt of the pyrazole may be used. The reaction may be carried out in water or organic solvents such as ether, hexane and benzene. If an organic solvent is used a hydrogen halide acceptor, such as a tertiary amine, must be present. The pyrazoles may be purified from the reaction mixture by conventional methods such as vacuum distillation or, where appropriate, recrystallization. In general, the pyrazole compounds of this invention are soluble in conventional organic solvents such as acetone, benzene, ether and the like.

EXAMPLES The following examples illustrate specific methods by which compounds of this invention may be prepared. Unless otherwise indicated, percentages are by weight.

EXAMPLE 1 10.0 g. of pyrazole and 34.5 g. of 1,1,2,2-tetrachloroethylsulfenyl chloride were added to a flask containing water. The aqueous mixture was stirred to about 19 hours at room temperature. The aqueous layer was then discarded and the organic layer was dissolved in chloroform and washed consecutively with dilute aqueous hydrochloric acid and water. The organic layer was then dried over anhydrous magnesium sulfate and filtered. The chloroform was removed from the filtrate at 60 C., 0.5 mm. Hg to give 33.9 g. N-(1,1,2,2-tetrachloroethylthio)-pyrazole.

The analysis of this compound was: Found (percent): chlorine 55.08, sulfur 12.7. Calculated (percent): chlorine 53.31, sulfur 12.06.

Other N-( 1,1,2,2 tetrahaloethylthio) pyrazoles were made using the general method illustrated by Example 1. These compounds and their analyses are reported in Table I.

1 Halogen analysis in meq./g.

The pyrazoles, especially the unsubstituted and nitrosubstituted compounds, of this invention have exhibited an exceptional ability for controlling bacterial plant pathogens. They are unexpectedly superior to other corresponding N-(polyhaloalkylthio)-pyrazoles, such as the N- (trihalomethylthio)-pyrazoles, as regards bactericidal activity. In tests against bacterial plant pathogens from such genera as Erwinia, Agrobacteria, Corynebacteria, Xanthomonas and Pseudomonas the compounds of this invention had ED s (eifective dosage for 50% inhibition) as low as 0.5 ppm.

This bactericidal activity is illustrated by the data in Table II. The method used to develop these data was as follows: Bacteria suspensions were prepared by washing a culture of the desired bacteria from an agar slant with sterile water into a vessel and further diluting the aqueous suspension to 250 ml. with sterile water.

4 The pyrazole to be tested was dissolved in acetone to TABLE III 500 p.p.m. and 30A of this solution was pipetted onto each of two surface areas on a plate covered with 20 ml. of Percemmhlbmon Emersons agar. The treated agar plates were then sprayed Mycelial drop Slide spore with the bacteria suspension and the plates were incu- 5 Compound P H R j bated for 44 to 48 hours at 24 C. The two treated areas of the plate were then observed for bacterialgrowth. The 100 97 90 100 100 pyrazoles effectiveness for controlling bacterlal growth in N-(trichloromethylthio) pyrazole s3 0 35 0 0 the tmated areas rated as or mdlcatmg the NorE.P=Pythium ultimum;H=Helminthosporium satz'vum; R=Rhiareas were completely free of bacterial growth and zoctom'asolani;M=Monili niafructiocla;A=Altemariasolani. mdlcatmg they were Completely overgrovfll- Other pyrazoles of this invention were tested by the For comparison, N-(tnchl rome y py was Mycelial Drop Method described above except that they also tested by thls methodwere dissolved in acetone to a concentration of 500 ppm.

TABLE II The results of these tests appear in Table IV.

Efiectiveness TABLE IV E. cart- I. syrin- Percent inhibition ovora gae Compound P H F R Compound:

N-(l,1,2,2-tetrachloroethylthio)pyrazole N-(1,l,2,2-tetraehloroethylthio)-4-n1tro- N-(1,1,2,2-tetrachloroethylthio)-3-methy1- pyrazole 100 90 100 onitropyrazole. N-(1,1,2,2'-tetraehloroethylthio)-3-me1;hyl-4 N-(1,1,2,2-tetraehloroethylthio)-4-nitronitropyrazole 100 100 98 100 pyrazole. N-(l',1,2,2-tetrachloroethylthio)-4bromo- Comparison compound: N-(trichloromethylthio) py az 100 97 l00 pyrazola. N-(l,1,2,2-tetrachloroethylth1o)-3,5-d1- methyll-bromopyraz e 100 100 78 100 N130,162,2-tetirachloroethylthio)-3-methyl-4- 00 94 100 rom razo e The pyrazoles of thls invention also exhibit excellent N41,1,figtetrachlomethylthm) 3,5 di fungicidal activity. They are remarkably and surprisingly methylpyrazole 100 94. 100 Superior to correspondmg N'finchlorometilylthp) pyr No'rE.-P=Pythium ultimum;H=H2Zmit2thosporiumsativum;F=Fusarazoles. The preferred compound of this invention, N- m ygporum; R=Rhizomnm 301m, (1,1,2,Z-tetrachloroethylthio) pyrazole, is also effective in fungicidal applications in which the present commercial addltlon to the sPeclfiC pp q s f9rmulatlons fungicide which contains an N-tetrachloroethylthio group Illustrated above, the Pyrazoles of Invention ay be is relatively ineffective. For instance, it may be applied as formulatfid and PP 111 bacterlcldffll funglcldal a vapor to stored grain, such as green corn, to control aI1101lntS, 'aS the F y be, by 0I1VeI1t1I1%1aYllmethd$ fungus diseases which attack h grain to bacteria, fungi or hosts, especially vegetative hosts such The fungicidal superiority of N-(1,1,2,2-tetrahaloethylas Plants, Plant Seeds, P p and like, Which are thio) pyrazoles over corresponding N-(trichloromethylfiy files? p A d y y y be thio) pyrazoles was illustrated by testing N-(1,1,2,2-tetra- Wlth q and camers as P solu chloroethylthio) pyrazole and N-(trichlorornethylthio) 1011s and dlspelslonsformulatlon s of these pyrazole under identical conditions by the following 40 pyraFoles may P 9011mm stablhzers Spreadmg agegnts, methods. wetting agents, stlckmg agents, fillers, other compatible pesticides and the like. MYCELIAL DROP METHOD As :will be evident to those skilled in the art, various This test measures the fungitoxicity of a compound in modifications on this invention can be made or followed, terms of its inhibition of fungus mycelial growth. Each in the light of the foregoing disclosure and discussion, pyrazole was dissolved in acetone to a 125 ppm. concenwithout departing from the spirit or scope of the disclotration. Equal volumes of this solution were applied to sure or from the scope of the following claims. the centers of each of three replicate paper discs inocu- What is claimed is: lated with the desired fungus mycelium and placed on 1. A pesticidal composition for controlling bacteria or potato-dextrose agar medium. Following this application fungi comprising a bactericidally or fungicidally effective the discs were incubated along with inoculated but unamount of a compound of the formula treated control discs at ambient temperatures until the R3 control discs were filled with mycelial growth. The fungicidal activity of the pyrazole was determined by compar- I mg the radii of mycelial growth away from the edges of I the treated and control discs. From this comparison a pert. fig: agiii i g on the relatlve mycelial growth areas where X is halogen of atomic number 17 to 35, R and R are individually hydrogen or alkyl of 1 to 4 carbon atoms, SLIDE SPORE GERMINATION METHOD and R is hydrogen, halogen of atomic number 17 to This method is described in the American ,phytopathm 35 or nitro admixed with an inert liquid or solid carrier logical Society Journal, vol. 33, pages 527432 1943 It th d f t b t hi h measures the fungitoxicity of compounds in terms of their me 0 9. con to mg ac ena W c comprises percent inhibition of fungus spores The general proce applllying a bacterlcldally effective amount of a compound dure was as follows: Each pyrazole to be tested was disof t e formula solved in acetone to a concentration of 10 p.p.m. These X X solutions were then pipetted into the wells of depression slides and allowed to dry. The wells were filled with a spore suspension of the specified test organism and incu- 2N X X bated in a moist chamber overnight. A group of 100 spores was ex mined n the n m er of p r ger where X is halogen of atomic number 17 to 35, R and R nated and not germinated was counted and recorded to show the biological activity in terms of the percentage inhibition.

The results of these comparative fungicidal tests appear in Table III.

are individually hydrogen or alkyl of l to 4 carbon atoms, and R is hydrogen, halogen of atomic number 17 to 35 or nitro to said bacteria.

3. The method of claim 2 wherein R R and R are hydrogen.

4. A method for controlling fungi which comprises applying a fungicidal amount of a compound of the formula where X is halogen of atomic number 17 to 35, R and R are individually hydrogen or alkyl of l to 4 carbon atoms, and R is hydrogen, halogen of atomic number 17 to 35 or nitro to said fungi.

5. The method of claim 4 wherein R R and R are hydrogen.

6. The method of claim 4 wherein X is chlorine.

7. The composition of claim 1 wherein X is chlorine.

8. The composition of claim 7 wherein R R and R are hydrogen.

References Cited UNITED STATES PATENTS 2,888,462 12/1959 Cannon 2603 10C 3,178,447 4/1965 Kohn 424273 10 3,409,632 11/1968 Fenyes 2603l0C ALBERT T. MEYER'S, Primary Examiner V. D. TURNER, Assistant Examiner 

